f.  // 


T.  S.  DEPAR  rMENT  OF  AGRICULTURE, 

BUREAU    OF    ENTOMOLOGY  -CIRCULAR   No.   171. 

L  O.  HOWARD.  F.nlomologia  «nd  Chief  olButemu. 


FIELD  OBSERVATIONS  ON  SUGAR-CANE  INSECTS 
IN  Till:  UNITED  STATES  IN  1912. 


BY 


T.  E.  BOLLOWAY, 

Entomological  Attit 


.TON  :  GOVERNMENT  PRINTING  OFTICE  :  191) 


B  UREA  V  OF  ENTOMOLOG  Y. 

L.  O.  Howard;  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chit  flu  Absence  of  Chief '. 

R.  S.  Clifton,  Executivi  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  fore  it  insect  investigations. 

W.  D.  Hunter,  in  charge  of  outhet  i  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  invt  filiations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 
E.  F.  Phillips,  in  charge  of  &< 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  uork. 
Rolla  P.  Currie,  in  charge  of  editorial  u 
Mabel  Colcord,  in  charge  of  library. 

Southern  Field  Crop  Insect  Investigations. 

W.  D.  Hunter,  in  charge. 

W.  D.  Pierce,  J.  D.  Mitchell,  G.  D.  Smith,  E.  A.  McGregor,  Harry  Ptnkus, 

B.  R.  Coad,  G.  N.  Wolcott,  W.  A.  Thomas,  R.  \Y.  Moreland,  C.  E.  Hester, 
engaged  in  cotton-boll  weevil  invi  I iga ' 

A.  C.  Morgan,  G.  A.  Runner,  S.  E.  Crumb,  D.  C.  Parman.  engaged  in  tobacco 

insect  investigation. 
F.  C.  Bishopp,  A.  H.  Jennings,  H.  P.  Wood,  W.  V.  King,  engaged  in  tick  investigate 
T.  E.  Holloway,  E.  R.  Barber,  engaged  in  sugar-cane  invect  investigations. 
J.  L.  Webb,  engaged  in  rice  in  ligations. 

R.  A.  CooLEY,  D.  L.  Van  Dink,  A.  F.  Conradi,  C  C.  Krumbhaar,  collaborators. 
[Cir.  171] 
U 


Circular  No.  171. 

United  States  Department  of  Agriculture, 

BUREAU  OK   ENTOMOLOGY 
L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


FIELD  OBSERVATIONS  ON  SUGAR-CANE  INSECTS  IN 
Till;  UNITED  STATES  IN   1912. 

By  T.  i:    Hoi  low  it, 

I 

ENTROD1  CTION". 

The  results  here  presented  are  based  on  the  records  of  field  observa- 
tions made  during  the  year  L912.  Though  the  information  on  any 
one  insect  is  fragmentary  ;ii  best,  it  has  been  thoughl  desirable  t<> 
issue  this  reporl  for  the  reason  thai  bo  little  is  definitely  known  con- 
cerning insects  affecting  sugar  cane  in  the  United  States  thai  even  a 
very  incomplete  treatmenl  of  the  Bubjecl  is  a  contribution  to  the  cur- 
renl  knowledge. 

\  irvey  of  the  sugar-cane  areas  of  Louisiana  and  Texas  was  under- 
taken during  the  year,  ami  this  work  has  been  supplemented  by  some 
observations  made  in  Mississippi  and  Alabama.  In  subsequent 
reports  more  attention  will  be  given  to  the  States  lasl  mentioned,  as 
well  as  to  Georgia  and  Florida,  In  it  the  pro-,  of  other  work  in  the  pasl 
has  rendered  it  impossible  to  give  these  States  the  attention  they 
deserve. 

Credit  and  the  thanks  of  the  writer  are  due  to  Mr.  K.  R.  Barber,  of 
this  bureau,  iov  making  a  number  of  field  examinations,  mainly  the 
final  observations  in  northern  Louisiana  and  those  in  Mississippi  and 
Alabama. 

■rm.    -i  G  \i: -i   wi.    moth    BORER. 

Special  attention  was  given  to  the  determination  of  the  percentage 
of  infestation  of  the  moth  borer,  this  being  the  principal  inseel  inju- 
rious to  sugar  cane  in  this  country.  The  plan  adopted  W8S  to  examine 
125  Btalks  of  sugar  cane  in  a  field,  choosing  the  stalks  in  5  differenl 
groups  of  25  stalks  each.  The  uninfested  and  the  infested  -talks  in 
these  groups  were  counted,  and  the  percentage  of  infestation  was 
determined  from  this  data.  In  actual  practice  this  proceeding  ' 
changed   to  some  extent.     More   than    l_'.")  stalks  were  sometimes 

Ir.  171-13  1 


2  l  EELD   OBSERVATIONS   OX    SUGAB  CANE   INSECTS. 

examined,  and  sometimes  it  seemed  preferable  to  examine  75  stalks 
in  each  of  two  fields  rather  than  to  concentrate  the  work  on  one  field. 
The  number  of  fields  examined  in  one  vicinity  varied  from  one  to  four, 
depending  on  the  amount  of  time  at  the  disposal  of  the  inspector. 
The  infestation  of  the  moth  borer  set  ms  to  be  fairly  uniform  in  a  given 
district,  and  it  is  believed  that  I  lie  results  obtained  give  a  good  idea 
of  the  relative  infestation  by  the  insect. 

Examinations  were  made  from  May  24  to  November  20,  1012.  It 
was  difficult  to  determine  the  full  infestation  of  the  moth  horer  during 
the  first  part  of  the  season,  however,  and  in  the  table  which  follows 
the  results  for  October  and  November  only  are  given.  Early  in  the 
season  the  cane  can  hardly  be  carefully  examined  without  damaging 
the  plant,  and  the  infestation  of  the  moth  horer  is  then  small  com- 
pared to  the  infestation  that  may  he  expected  later.  The  dates  of 
inspection  are  given  in  the  table  because  the  infestation  seems  nor- 
mally to  increase  until  the  cane  is  cut.  Thus  the  infestation  of  a 
certain  field  would  probably  be  greater  on  November  1  than  on 
October  1.  Comparisons  of  the  different  percentages  can  be  made 
more  accurately  if  this  is  kept  in  mind. 

Table  showing  the  jk ra  ntagt   of  sugar  cane  infested  by  the  moth  borer  at  various  places 

i  he  Souther  a  States  itt  1U12. 


State. 

Near  town  ot  city  of 

Parish  or  county. 

Date  of 
Inspec- 
tion. 

Per  cent 

of inf  sta- 
tion. 

Louisiana 

Alexandria 

Nov.    8 
on.    29 

Nov.    7 
Oct.    2s 

....do.... 

0 

Baton  Kouge 

78 

Iiunkie 

0 

56 

do 

59 

81    Mur\ 

Oct.  31 

Oct.    30 
Nov.    1 
Oct.    17 
Nov.  11 
Nov.  12 
Oct.     7 
Oct.     8 
Oct.    y 

Nov.  13 
Oct.   12 
Oct.    11 
Oct.   27 
Nov.  IS 
Oct   24 
Nov.  14 
Oct.    28 
...do.... 

47 

57 

St.  Mary   

4 

X.  u  Orleans 

59 

Lincoln   

0 

Caddo 

0 

62 

Hidalgo 

99 

88 

San  Benito 

do 

61 

Fort  Bind 

0 

0 

Mississippi 

0 

Lincoln     

0 

Hattiesburg 

0 

0 

Alabama 

0 

Dallas 

0 

The  foregoing  table  indicates  that  the  infestation  of  the  moth  borer 
varies  from  99  per  cent  (or  practically  all  canes  infested)  at  a  point 
in  the  Rio  Grande  Valley  in  Texas  to  0  per  cent  (or  no  canes  infested) 
at  places  in  northern  Louisiana,  Alabama,  and  Mississippi,  and  even 
at  Sugar  Land  and  Victoria,  Tex.  At  Victoria  our  notes  are  corrobo- 
rated by  Mr.  J.  1).  Mitchell,  a  resident  agent  of  the  Bureau  of  Ento- 
mology, and  planters  near  there  are  entirely  unfamiliar  with  the  moth 

[Cir.  171] 


I  hi  n   0B8I  i:\  \  i  10! 

borer.     Cane  baa  been  grown  for  - 

and  it  ia  unlikelj  thai  anj  new  varieties  have  been  in 

in  11  general  ion. 

I      ,ema  evident  from  tl  thai  the  moth  borer 

never  entered  certain  restricted  districts,  while  il  has  probablj  I" 
hnported  with  shipments  of  »eed  cane  to  places  where  an  efforl  i 
been  made  to  obtain  new  and  better  v<  ne.     The  preset 

,,f  the  moth  borer  in  Louisiana  >unted  for  l>.\  the  belief  that  il 

.  introduced  in  shipment  "!'''-•  uhl1, 

,  ,„ ...  hi  the  Rio  Grandi   \  probably  due  to  accidental  inti 

ductioua  from  Louisiana  or  Mexico,  provided  it  is  not  native  to  tb 
pari  of  Texas.     However  this  maj   be,  the  moth  borer  is  evidently 
absenl   from   the  sirup-producing  regions  of  Texas  and   Louisiana, 
where  sugar  cane  is  grown  only  as  an  incidental  crop,  while  the  insi 
i>  preeenl  in  the  BUgar-producing  regions  (except  at  Sugar  Land    wl  ■ 
Bugar  cane  is  of  vital  importance  and  where  ne*  and  better  varieties 
are  desired  and  obtained.     The  results  from  examinations  in  Ala- 
lia and  Mississippi  concern  sirup-producing  communities,  ai  i 

esults  from  Texas  and   Louisiana.     These  findings  go  to 
Btrengthen  the  position  that  introductions  e  should  be 

made  with  greal  care  if  injurious  re  to  be  excluded. 

A  most  noteworthy  result  of  the  examinations  during  the  year  is 
the  discovery  of  eggs  of  the  moth  borer  I  by  the  hymen 

•us   parasite    2  mma    minutum  Riley,    by    Mr. 

Gilbert  E.  Bodkin,  Government  economic  biologist  of  British  Guiana, 

ii.-.,.     Examining  sugar  cane  with  the  writer  ai  Audul 
p  ,  ans,  in  September,  he  found  the  black  egg  m 

the  moth  borer  on  the  leaves  of  the  planl        B  miliar  with  the 

work  of  the  parasite  in  British  Guiana  he  was  sure  that  tl 
parasitized.     Parasites  were  afterwards  reared  from  the  eggs  by  the 
writer,  and  they  were  found  to  be  of  th<  ned,  which 

occurs  in  many  place-  in  this  and  other  countries.     The  parasite, 
however,  had  not  previously  been  reared  from  the  moth  borer 

iu  the  United  S 

Later  the  writer  found  parasitized  eggs  of  the  moth  borer 
Brownsville,  Tex.,  Donna.  Tex.,  Donaldsonville,  La.,      -1  Franklin, 

The  larvae  of  a  predaceous  hectic  were  found  on  sugar  cane  by 
Mr.  !•"..  R.  Barber,  near  Montgomery,  A  October  26,  and  by  the 

writer  near  Baton  Rouge,  La  .ami  La  Fayette,  La.,  in  October,  and 
near  San  Benito.  Tex.,  in  November.    These  larvae  were  not  i 
to  attack  the  borer,  though  they  may  do  - 

Evidences  of  larval  pai  number 

of  places,  but  these  are  somewhat  doubtful. 

1T1] 


4  FIELD   OBSERVATIONS   OX    SUGAR-CANE   INSECTS. 

THE    SUGAR-CANE    MEALYBUG. 

(Pseu/docorru.s  calceolaria  Mask.) 

The  examinations  to  determine  the  infestation  of  the  mealybug 
were  made  chiefly  in  connection  with  the  work  on  the  moth  borer. 
The  mealybug  appeared  in  small  numbers  at  the  experiment  station 
at  Audubon  Park  during  the  summer  of  1912,  and  by  November  26 
it  was  difficult  to  find  a  single  stalk  of  the  cane  then  on  the  fields 
which  was  entirely  free  of  the  insect.  Near  Poydras,  St.  Bernard 
Parish,  La.,  a  few  mealybugs  were  found  on  one  stalk  of  cane  on 
September  10.  On  September  12  a  small  infestation  was  found  in 
Jefferson  Parish,  near  New  Orleans  (on  St.  Martin  plantation).  The 
mealybug  in  fairly  large  numbers  was  found  by  Mr.  E.  R.  Barber 
at  English  Turn,  Plaquemines  Parish.  La.,  on  September  24.  Near 
Franklin,  La.,  the  writer  found  a  slight  infestation  on  October  31. 
The  green  fungus  which  attacks  the  mealybug  was  observed  at  two 
places  in  Orleans  Parish,  La. 

The  mealybug  was  discovered  by  the  writer  at  Brownsville,  Tex., 
for  the  first  time  on  October  S.  A  rather  heavy  infestation  occurred 
on  a  limited  number  of  canes  of  various  new  varieties  at  the  experi- 
ment station.  The  bisect  had  evidently  been  brought  hi  with  the 
cane  from  Louisiana  or  the  Tropics.  The  infested  cane  was  soon  after 
destroyed  by  those  in  charge  in  an  effort  to  eradicate  the  mealybug 
from  the  experiment  station  grounds. 

It  is  evident  that  the  mealybug  has  infested  only  a  limited  territory 
in  the  United  States.  Precautions  should  be  taken  to  prevent  its 
spread  to  uninfested  regions.  The  problem  of  the  mealybug  is  com- 
plicated in  certain  parts  of  Louisiana,  where  the  Argentine  ant  (Irido- 
myrmc.r  humilis  Mayr)  also  occurs,  as  the  two  species  are  of  benefit  to 
each  other,  and  the  ant  aids  in  the  spread  of  the  mealybug. 

THE    SUGAR-CANE    WEEVIL    BORER. 

Concerning  the  weevil  borer  we  quote  our  remarks  in  another 
circular,1  which  are  as  follows : 

A  note  in  the  possession  of  the  •writer  records  a  weevil  as  having  been  reared  from 
young  shoots  of  sugar  cane  which  were  collected  at  Fairview  Plantation,  Berwick. 
La.,  on  April  28,  1910,  by  Mr.  D.  L.  Van  Dine.  Mr.  Van  Dine  found  the  lame  just 
above  the  surface  of  the  ground.  Mr.  E.  R.  Barber  of  this  office  states  that  he  found 
pupae  of  weevils  in  the  sugar  cane  at  Audubon  Fark.  New  Orleans,  in  1911.  During 
the  early  summer  in  1912  the  writer  found  weevil  borers  in  the  young  sugar-cane 
plants  at  Audubon  Park  and  at  the  experiment  station  at  Brownsville.  Tex.     The 

1  Insects  Liable  to  Dissemination  in  Shipments  of  Sugar  Cane.    By  T.  E.  Holloway.    Cir.  165,  Bur. 
Ent.,  U.  S.  Dept.  Agr.,  1912. 
[Cir.  171] 


FIELD   OBSERVATIONS    OS    BUOAR-CAN1     IN8E(    TO.  D 

Qi  fouu  '  na^  ill''  were  in  the  lai  bble 

(.in..  I.,  l.  u  the  nurface  "i  the  ground,  and  Dear  the  poinl  where  il" 
left  the  old  etubble     in  plant  caneal  Audubon  Parli  the  weevil  lai  und 

below  tin-  surfai  •■.  and  near  the  poinl  where  the  young  plant  joined  the  seed  i 

The  Ian  e  were  from  one-eighth  i te  fourth  oi  an  Inch  In  lengtb     Bonn 

borer  was  found  in  the  middle  of  the  stem,  while  in  other  cases  the  borera  were 
one  aide  of  the  stem.    The  injur)  to  the  plant  [alike  the  "dead  heart  'caused  by  our 
moth  borer,     it  seems  probable  that  the  moth  borer  ia  blamed  i"i  some  oi  the  injury 
caused  by  the  weevils. 

Very  likely  th  era  have  ' n  Introduced  In  shipment  e  from 

the  Tropica     They  are  small,  and  tlnir  w.rk  ia  lui r. i  to  find,  so  that  they  d 
easily  have  escaped  the  eye  of  the  average  person  ila  have  been 

found  up  to  date  that  there  may  be  do  oi  casion  for  alarm,  while  on  the  other  hand 
they  may  Increase  In  numbei  become  b 

Till.    PALL    AltMY    WORM. 

Laphygmafrugiperda  S  a  \ 

Following  the  wel  weather  of  tin'  spring  of  1912  an  outbreak  of 
tin'  fall  anny  worm,  or  southern  grass  worm,  was  noticed  in  the 
Southern  States.  Corn,  rice,  ami  forage  crops  suffered  more  than 
sugarcane,  hut  i>m>  field  of  cane  thai  tame  under  the  writer's  observa- 
tion was  ruined  by  this  or  a  nearly  related  specie-.  This  held  was 
near  La  Fayette.  La.,  and  was  examined  on  .Inly  20,  I'M-'.  The 
land  was  comparatively  low  ami  undrained,  thus  providing  a  suitable 
place  for  the  development  of  the  "grass  worm."  which  prefers  a 
soil.  The  characteristic  work  of  the  larvaa  was  observed,  though  no 
larva1    were    found.      LarvSB,    however,    were    found    attacking    SUJ 

cane  at  Audubon  Park.  New  Orleans,  during  July,  1912. 

In  most  cases  it  seems  that   no  great   injury  from  this  Bpeciea  was 

Buffered  by  Bugarcane,  and  the  plants  recovered  so  completely  that 

in  the  grinding  season  the  injury  was  hardly  perceptible,  and  only  a 
few  leaves  could  ordinarily  he  found  showing  traces  <>f  the  work  of 
the  larvae. 

I  III.    -i  i;  LR-CANE    BEETLE. 

No  definite  records  have  been  obtained  during  the  year  regarding 
the  Bugar-cane  beetle,  and  it  is  probable  that  it  has  done  very  little 

damage  this  season. 

May  beetles  (Lachnosterna  spp.)  are  also  known  to  attack  su«rar 
cane,  hut  no  injury  due  to  them  was  observed  during  the  year,  ami 
Very  few  adults  of  the  beetles  were  seen  at    New   Oilcan-. 
[Clr.  171] 


0  FIELD   OBSERVATIONS   OX    SUGAR-CANE   INSECTS. 

THE    SUGAR-CANE    APHIDID. 

Winged  and  wingless  forms  of  a  dark  brown  aphidid,  or  plant  louse, 
were  observed  on  sugar  cane  at  Audubon  Park,  New  Orleans,  on 
July  29,  1<)12,  and  at  various  times  thereafter.  They  were  attended 
by  the  Argentine  ant  in  the  same  way  as  the  mealybug  is  attended  by 
this  species.  Very  little  is  known  concerning  tbis  aphidid.  It  is 
found  in  small  colonies  on  the  outside  of  the  leaf  axils  on  the  cane 
plant,  and  apparently  works  in  a  manner  somewhat  similar  to  that  of 
the  mealybug,  though  it  has  been  observed  on  the  leaves  of  the  cane 
rather  than  on  the  stalks  themselves.  In  large  numbers  tbis  species 
might  be  injurious  to  the  eyes  of  cane  for  planting. 

These  aphidids  were  also  found  near  Donaldsonville,  La.,  Franklin, 
La.,  llarlingen.  Tex.,  Morgan  City,  La.,  and  Poydras,  St.  Bernard 
Parish,  La. 

INSECTS    OF    MIXOR    IMPORTANCE. 
ANTS. 

The  large  red  ant  of  Texas  (Pogonomyrmex  barbatus  Smith),  usually 
called  the  agricultural  ant,  was  recorded  during  the  year  as  attacking 
sugar  cane.  Near  Brownsville,  Tex.,  on  June  12,  the  writer  observed 
ants  of  this  species  busily  gnawing  a  few  young  cane  plants.  The 
sound  they  made  was  similar  to  that  of  a  gentle  shower  of  ram.  The 
ant-  bad  eaten  the  leaves  of  plants  about  2  feet  high,  as  well  as  the 
entire  tops  of  two  little  plants  about  one-eighth  inch  hi  diameter. 
This  seems  to  be  an  exceptional  habit  on  the  part  of  the  agricultural 
ant. 

Another  species  of  ant  was  found  nesting  in  holes  in  cane  stalks 
made  by  the  moth  borer  and  in  the  spaces  between  the  leaves  and  the 
stalk-.  This  observation  was  made  near  Brownsville,  Tex.,  on  Octo- 
ber 7,  1012. 

These  ants  should  not  be  confused  with  the  Argentine  ant,  which 
is  of  prime  importance  in  its  symbiotic  relationship  with  mealybugs, 
scale  insects,  and  aphidids. 

LEAFHOPPERS. 

Leafhoppers  in  very  small  numbers  were  observed  several  times 
during  the  season  on  sugar  cane,  but  no  injury  due  to  them  could  be 
detected. 

FROGHOPPERS. 

Mr.  Gilbert  E.  Bodkin  and  the  writer  found  froghoppers  on  sugar 
cane,  weeds,  and  grass  near  Poydras,  St.  Bernard  Parish,  La.,  on 
September  10.  1012.     The  froghoppers  start  on  rank  growth  and  then 

.  171] 


Ml  i  |.   OB    I  >:'    IT1<  OAR-CANE  1  7 

transfer  their  attention  I  cane      Forth]   reason  the  fields  should 

be  kepi  free  of  weeds  and  I  peciallym  moist  situatioi 

humid  climate  is  favorable  to  the  development  of  these  ins< 

■ 

The  writer  found  termites  or  "white  ants"  in  sugar  cane  which 
bad  been  cut  into  pieces  of  three  joints  each  and  planted.  <>u 
June  12,  1912,  when  some  of  the  cane  wa    dug  up  and  examined,  the 

shoots  from  it  were  apparently  weak  and  some  of  tl yes  had  nol 

germinated.  The  cane  was  plantod  neai  Brownsville,  Tex  .  and  had 
been  imported  from  Porto  Rico,  but  the  writer  believes  that  the 
termites  were  probablj  native  to  this  country  and  that  they  attacked 
the  cane  readily,  being  attracted  by  the  many  cuts.  Ii  seems  inad- 
visable from  the  entomological  standpoint  to  cut  cane  in  Bmall  pie 
before  planting,  as  many  insects  may  easily  gnaw  into  the  Btalks 
through  the  unprotected  ends. 


On  August  9,  1912,  Mr.  E.  R.  Barber  found  grasshoppers  very 
abundant  in  the  cane  fields  near  Sugar  Land,  Tex.  Many  strip] 
leaves,  due  to  their  work,  were  seen.  The  writer  visited  Sugar  Land 
on  October  12,  but  found  no  grasshoppers  at  that  time.  The  cane 
ned  to  have  recovered  from  the  injury  it  had  suffered  earlier  in 
the  season  from  these  insects.  A  grasshopper  in  the  act  of  gnawing 
a  cane  leal'  wa-  observed  near  Baton  Rouge,  La. 


<  ONCLl  SIONS. 


The  peculiar  weather  during  the  season  of  L912  probably  accounts 
in  |>art  at  Least  for  certain  unexpected  developments  in  insect  life 
during  the  year.  A  long  ami  cold  winter  was  followed  in  Louisiana 
by  a  wet  spring.  Breaks  in  the  lever  of  the  Mississippi  River  caused 
vast  area-  of  land  to  he  flooded,  ami  the  excess  of  water  complicated 
matter-  further.  We  find  a  -low  development  of  the  moth  borer 
ami  the  mealybug,  which  are  tropical  species  and  evidently  require 
a  greater  amount  of  warm  weather  than  our  native  insects.  A-  to 
the  Bugar-cane  hectic,  the  statement  ha-  been  math'  by  some  plant 
that  this  inseel  does  most  damage  in  dry  seasons  and  on  high,  sandy 
soil-,  30  that  we  may  believe  that  the  wet  weather  retarded  it- 
development.  The  fall  army  worm,  or  southern  grass  worm,  on  the 
contrary,  i-  more  injurious  during  wet  weather,  which  will  account 
for  it-  extraordinary  abundance  during  the  summer  ^>\'   1'"-'. 

Practically  no  moth  borers  or  mealybugs  were  found  in  the  dis- 
trict near  Morgan  City.  La.,  which  had  been  overflowed  some  months 

(Cir.  171] 


8  FIELD   OBSERVATIONS   ON    SUGAR-CANE   INSECTS. 

previous  to  our  observations.  This  indicates  that  these  insects 
may  possibly  be  controlled  by  flooding  or  excessive  irrigation. 

Though  these  inferences  are  mainly,  perhaps,  of  scientific  interest, 
they  may  at  some  time  be  useful  in  an  economic  way.  More  impor- 
tant from  the  planter's  point  of  view,  however,  is  the  evidence  of 
the  uneven  distribution  of  the  principal  insects  which  are  injurious 
to  sugar  cane.  It  seems  that  with  reasonable  caution  in  the  ship- 
ment of  cane  the  spread  of  most  species,  at  least,  can  be  curtailed 
if  not  altogether  prevented. 

The  number  of  species  which  were  detected  injuring  cane  is  per- 
haps surprising,  and  it  is  possible  that  still  other  species  will  be 
discovered  as  the  work  progresses.  Some  of  the  species  are  appar- 
ently of  no  great  importance,  though  there  is  a  possibility  that  the 
weevil  borer  and  the  froghopper,  which  are  now  rare,  may  increase 
in  numbers  and  become  formidable  pests.  The  aphidid,  also,  which 
is  rather  widely  distributed,  is  to  be  regarded  as  an  insect  which 
may  be  capable  of  considerable  injury. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  January  18,  1913. 

[Cir.  171] 


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